Ed O'Brien's cousin passed away while he was recording Earth
; this song finds him reflecting on the inevitability of death. He told NME
"I'm like any other human being - I don't think there are any writers that have anything totally new to say. It's just the way you frame it. There is a universality to human experiences. What I'm saying in 'Sail On' is a personal thing, but it's about death, dying, the soul and the spirit. My feelings on that are as old as the wind. If you decide that you have to make music or art, then you're looking for the truth, not perfection."